Microfluidic technology has the potential to revolutionize experimentation with living cells in vitro. Numerous studies providing proof-of-principle for novel high-quality cell assays based on microfluidics have been published over the past decade. A good set of examples of what microfluidics has to offer modern biology are the increasing number of assays designed to allow formation of predictable concentration gradients in different cell culture setups. Concentration gradients of signaling molecules are central to cell-cell communication in all multicellular organisms. In many of the microfluidic cell culture systems, the fluidic channels and the cavities for cell culture are created in polydimethylsiloxane (PDMS) sealed by bonding to a glass surface. These assays enable real-time studies of cell migration, proliferation and differentiation in response to concentration gradients of soluble signaling molecules (often proteins), in both two- and three-dimensional settings. Conceivably, some of these new methods based on microfluidic technology could become new global standards, and thereby in part replace techniques such as, for example, the Boyden chamber assay for the study of chemotaxis.
The market for microfluidic cell assays and applications has considerable growth potential. This is in part propelled by the need for new in vitro systems in academic research to better replicate biological processes, but also because of an increasing demand from regulatory authorities for improved cell-based screening of chemical compounds in the process of drug development. However, in spite of the great promise of microfluidics to both improve and accelerate biological research, the commercial impact so far is small.
A main reason for the modest use of microfluidics in various cell culture applications is likely that most microfluidic assays of today are fairly difficult to set up and operate for non-expert users. There is however a growing body of simplistic and commercially available systems, and several companies such as BellBrook Labs (WI, USA), Xona Microfluidics LLC (CA, USA) and Ibidi GmbH (Germany) have fluidic devices for cell studies on sale.
US 2008/0194804 discloses a microfluidic chip-based hybridization device. The device consists of an upper basal plate, a lower basal plate and a substrate that are stacked together. The upper basal plate has a hybridization region in which the substrate is positioned. A central inlet/outlet hole runs through the middle of the hybridization region, which is further connected to a microfluidic channel that is linked to another inlet/outlet hole.
US 2007/0125434 relates to a microfluidic device capable of preventing the flow of fluid from being interrupted by bubbles generated in a micro flow passage. A narrow portion of the micro flow passage is formed by arranging a columnar portion in the micro flow passage. The bubble trapping means is a recessed portion which is formed in an upper surface of the micro flow passage upstream of the columnar portion.
US 2008/0102478 discloses a polymeric chip having multiple three-dimensional porous scaffolds, a microfluidic channel inlet to the porous scaffold and a microfluidic channel outlet from the porous scaffold. The chip is designed to be used as a multi-organ tissue model system.
However, there is still a need for a versatile microfluidic capsule that enable easy assembly and operation of microfluidic substrates.